593
FXUS63 KFSD 051722
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1122 AM CST Mon Dec 5 2016
.SHORT TERM...(Today and Tonight)
Issued at 324 AM CST Mon Dec 5 2016
A mild but breezy day is expected today ahead of a vigorous upper
low moving through the northern Plains this evening and tonight.
Strengthening pressure gradient at the surface will initially bring
gusty south southwest winds this morning, however a boundary
arriving in south central South Dakota around midday will quickly
advance east across the entire forecast area this afternoon through
mid evening. Winds shift to the northwest and remain quite windy
into the overnight hours. Frontal passage looks largely dry, however
models suggest that mid level frontogenesis does become a little
better organized across the Spencer/Storm Lake area in Iowa mid to
late afternoon. This may allow a few light rain showers or sprinkles
to develop briefly, before moving east early evening.
Mixy conditions today will allow temperatures to warm into the 40s
to near 50 despite the mostly cloudy skies. Did raise highs a few
degrees near and east of the I-29. Earlier arrival of the cold air
advection associated with the brisk northwest flow will likely cap
temperatures cooler in south central SD. Temperatures will steadily
drop overnight as the cold air advection begins arriving. By
daybreak Tuesday, temperatures will be in the upper teens to mid
20s.
.LONG TERM...(Tuesday through Sunday)
Issued at 324 AM CST Mon Dec 5 2016
Cool and breezy conditions will dominate the forecast in the Tuesday
through Thursday time frame behind a cold front moving through the
area. Have raised winds through the period by loading CONSMOS.
Potential for a little light snow or flurries through the period
with deep dendritic layer near the surface. The first is on Tuesday
in the north as the upper trough moves from the eastern Dakotas into
the western Great Lakes. The second period for light snow appears to
be on Thursday morning as piece of energy rotates down through
Minnesota in deep northwest flow.
With the lack of snow cover, have stuck close to guidance values,
but have dropped lows a few degrees.
Pacific NW wave moving through the region Friday night into Saturday
appears to be much less organized than it was in the previous runs,
so have only continued slight chance to chance pops. Towards the
second half of the weekend, more seasonal air appears to work back
into the region, resulting in temperatures warming towards seasonal
norms.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1119 AM CST Mon Dec 5 2016
MVFR ceilings will likely move in and move out this evening, but
then reappear again on Tuesday morning. North of Interstate 90
these MVFR ceilings have a better chance of remaining all night
into Tuesday morning. Scattered flurries or patchy light snow
will be possible on Tuesday as the cold air continues to
strengthen and deepen. One concern will be very strong west to
northwest winds from this evening into Tuesday with gusts around
40 mph likely.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...
LONG TERM...BT
AVIATION...08